Variable hydraulic pump or motor



June 28, 1949.. Y J. E. LUNDEGARD 2, 74,536

VARIABLE HYDRAULIC PUMP 0R MOTOR F l 'ja Feb. 17, 1945 4 Sheets-Sheet 1 Zhwentor dorm E'.- LUNDE GARD attorneys J1me 9 9- J. E, LUNDEGARfi 2,474,536-

VARIABLE HYDRAULIOPUMP OR MOTOR Filed Fe b. 17 1945 4 Sheets-Sheet 2 Snnentor JOHN E. LUNDEGARD attorney;

June 28, 1949 Filed Feb. 17, 1945 J E. LUNDEGARD VARIABLE HYDRAULIC PUMP 0R MOTOR 4 Sheets-Sheet s Snventor JOHN E-. LUNDEGARD June 28, 1949. 5 LUNDEGARD 2,474,536

VARIABLE HYDRAULIC PUMP OR MOTOR Filed Feb. 17, 1945 I 4 Sheets-Sheet 4 ZSnnentor attorneys Patented June 28, 1949 UNITED STATES ATENT OFFICE VARIABLE HYDRAULIC PUMP OR MOTOR John E. Lundcgard, Bremerton, Wash.

Application February 17, 1945, Serial No. 578,482

Claims.

This invention relates to hydraulic means for transmission of power, and is illustrated in the form of a variable delivery hydraulic pump and companion motor. Similar principles are in-- volved in both the pump and the motor, either of which constitutes a hydraulic power transmission unit.

More particularly the present invention concerns such a unit in which pistons are reciprocable in radial cylinders in a rotor, the length of the pistons stroke being governed by the eccentricity of an eccentric disk, to which the pistons are connected, relative to the rotor.

In previous devices of this general nature, the interconnection between the pistons and the cocentric disk has constituted the sole connection between the rotor (wherein the pistons reciprocate) and the eccentric disk, though an indirect one. The linkage connecting the pistons and the eccentric disk had to be arranged (a) to eifect in and out movement of the piston Within its cylinder, (b) to accommodate translational movement of the axis of the cylinder into and from coincidence with the axis of the eccentric disk during each revolution, and (c) to drag the eccentric disk around with the rotor and to maintain the disk in such proper operative relationship to the rotor that it will serve as a proper reaction point for the radial thrust upon the piston.

It has been found that these requirements become mutually repugnant at times. The necessity for dragging around the eccentric disk tends to tension the linkage, while at the same time the necessity for pushing outwardly the piston requires the imposition of thrust on the linkage, and reaction from an already lagging disk. When two links are used at opposite sides (angularly) of the piston, in certain rotated positions one is in tension and the other in compression, with the result that a bending moment is imposed upon the piston, tending to bend it, and to make it stick within its cylinder. By thus imposing plural functions upon such connections, they can not properly perform any one function with entire satisfaction, nor efficiently. Inefliciency is manifested, for example, in the production of mutually opposing rather, than assisting forces, and in the production of destructive and wearproducing forces, such as that which causes the piston to tend to cook and stick.

It is a primary object of the present invention to avoid such difiiculties by completely divorcing the forces and mechanism for producing reciprocation of the pistons from those which effect conjoint rotation of the eccentric disk with the rotor. More particularly, it is an object, in addition to whatever mechanism may be provided to reciprocate the pistons, to provide a positive interconnection or interlock directly between the eccentric disk and the rotor, as distinguished from the indirect connection heretofore employed by way of the piston, and to assign to such interconnection or interlock the sole function of effecting conjoint rotation of the eccentric disk and rotor. Still further, it is an object to do this in a manner which avoids any slack between the disk and rotor, and thereby to afford a reaction base in the eccentric disk, solidly reacting in turn from the rotor, to effect reciprocation of the pistons.

By thus divorcing the control of the pistons from the control of the eccentric disk, the mechanism which effects reciprocation of the pistons can be made solely to perform that function, and hence can be made more efficient to that end. As has already been noted, the linkage in former constructions by which the pistons were reciprocated caused them to cook within their cylinders, but since this same linkage had also to drag about the eccentric disk such cocking was considered unavoidable. More especially was it considered unavoidable for the reason that a connection reasonably free from slack was considered necessary, and hence while the interconnection between the pistons and the eccentric disk necessarily required that some relative movement be permitted to accommodate the translational movement of the disk relative to the several pistons axes, this relative movement was kept to a minimum. In the present invention full freedom for relative movement may be given the pistons and the eccentric disk, because the disk and the rotor are otherwise (by the interlock) held for conjoint rotation without slack. Other prior devices have attempted to avoid such difficulties by forming each cylinder independent of the others so that they might vary in their angular spacing relative to one another as they revolve about the rotors axis, but this involves complications of manufacture, assembly and packing, and in addition involves the use of large, heavy, and expensive bearings, generally arranged peripherally around the rotor and the orbit of the pistons outer end. The linkage arrangement is therefore preferable, provided it can be so arranged as to avoid cocking of the pistons, and in the present invention, because the disk and rotor are otherwise interconnected for rotation, it can be. A further object of the present inven- 0 tion, therefore, is to provide a linkage connection between the piston and the eccentric disk, while yet avoiding the complications of forming the cylinders separately, and in the aggregate to provide a simple unit of the general character indicated, and one which avoids the production of sidewise forces on the pistons.

As has been indicated above, the necessity of providing numerous, heavy and expensive bearings in prior devices of this nature has been found a deterrent to their use, and has added tremendously to their cost. One other object of the present invention is to provide a construction in which the bearing forcesare. slight, the rate of relative movement of one element within another, and the wear, are negligible, and in which the necessary antifriction bearings can be largely reduced in essence simply to those which support the opposite ends of the rotor shaft, thereby greatly reducing the cost, complexity, and weight of the unit and greatly increasing its usefulness and availability, and its ruggedness.

With particular relation to such a unit, when arranged as a pump, it is an object of the invention to provide a unit which maybe adjusted in a 0 simple manner between any two limits, as for in.- stance, Zero and an upper limit, and indeed, to. provide a pump which without complications may be adjusted to desired limits at each side of zero, to the end that the pumps delivery may be reversible at will, to effect reversal of the motor while the pump continues to be driven in its normal rotative sense.

With particular reference to two such units,

interconnected to constitute a hydraulic trans- 1 mission device, it is a further object to provide two such units which may be made for the most part of identical elements similarly finished and assembled, so that the difference between the pump unit and the motor unit is largely one of .g,

adjustment of the eccentricity of the eccentric disk and of the companion interconnecting means between the disk and the rotor. In this way a minimum of diiferent parts are needed for the complete system.

' Further in connection with such, a pump unit which is adjustable, it is an object to. arrange the interconnecting means between the eccentric disk and the rotor in such relationship to the eccentricity of the disk that there will result similar acljustment of eccentricity of the interconnecting means simultaneously with adjustment of the eccentricity of the disk, through the interconnecting means, and in such manner that there will be maintained proper interconnection between the eccentric disk and rotor, without any appreciable slack, in any and all adjusted positions of the eccentric disk.

Another object of the invention is to provide such a hydraulic unit assembled from a minimum number of parts, and from parts which in themselves are simple to manufacture and to assemble, and which lend themselves readily to precision manufacture even on a quantity basis.

Generally speaking then, it is an object of the present invention to provide'a hydraulic unit of the general nature indicated which is simple, compact, light in weight, and inexpensive, and which is capable of operating with a minimum of friction and a maximum of reliability over long periods of time, whereby such units may be furnished in themselves, or as elements. of a hy draulic power transmission unit, at low cost and for use in many installations where heretofore such hydraulic power transmission systems were unsuited, for reasons of cost, weight, and the like.

Other objects will appear as this specification proceeds.

In the accompanying drawings the invention has been shown in a form which at present is preferred by me, but the showing is not intended as a practical or commercial embodiment of the invention. Rather, the showin is simplified and modified, as for example, by omission of bearing and lubrication details, seals, and the like, in order the better to illustrate the principles of the device. The supplying of such details is a matter within the skill of a competent designer.

Figure l is a perspective view of two companion units interconnected to constitute a hydraulic power transmission unit, in which the rate of delivery of the pump is variable in accordance with its setting, the volumetric capacity of the motor being constant.

Figure 2 is an axial section through the pump unit of such a combination, and Figure 3 is a transverse section through the pump unit, substantially along the line 3-3 of Figure 2.

Figure 4 is a. sectional view transverse to the axis of rotation, along the plane defined by the axes of the cylinders and their pistons, but showing, in this instance, the motor unit.

Figure 5 is a transverse section corresponding to Figure. 3, but. taken through the motor unit.

Figure 6 is an axial section corresponding to Figure 2, through the motor unit.

Figure 7 is a detail section. taken at so degrees about the axis of the: rotor from the section of Figure 6, showing the hydraulic fluid inlet and outlet.

Figures 8 to 14, inclusive, are perspective views of individual parts, as will appear from the description; Figure 12 is an exploded View of one such part.

Figure 15- is a geometrical layout or diagram of a unit of the device.

The device as a Whole, shown in Figure 1, comprises a pump P connected by conduits A and B with a motor M. These conduits may be considered, respectively, as delivery and return conduits, though such functions may be reversed, as will later appear. The pump P' and motor M may be widely separated, or more closely spaced. The shaft to" of the pump is driven from a suitable power source, usually at a constant speed, causing fluid to be delivered by way of the conduit A from the pump to the motor M, and to be returned thence by the conduit B, at a rate of delivery which is a function of the eccentricity of the rotor and eccentric disk within the pump. However, since in the motor the rotor and eccentric disk are normally set-during manufacture at. a constant eccentricity, the motor shaft it will be rotated at a rate of speed which is a function of the relative delivery and absorption rates of the. pump and motor, respectively. Adjustment of the delivery rate of the pump is accomplished by adjustment of its rotor within the casing 8' with respect to a fixed guide frame 98 by means such as the. rod 98. Reversal of the motor sense of rotation will be governed by reversal of the position of the rotor with respect to a zero point,

By referring to Figures Ito 8 it will be seen that the rotor I, having the shaft I and hub H projecting axially from its opposite sides, is formed with a plurality of radial cylinders I2, in each of which is reciprocable a piston 2. Each cylinder 12 stops short of the periphery of the rotor, and its outer end constitutes a guide for a crosshead 20 carried by the outer end of each piston. The rotor is provided with a series of apertures I5, which are cylindrical in shape, and their axes are parallel to the axis of the rotor. The purpose of these apertures I will shortly appear. The hub II of the rotor, at the end opposite its shaft II], is bored, parallel to the axis, to provide individual passages I3, each of which admits to the inner end of the corresponding cylinder, and connects this cylinder with the passage A or B, as the case may be, according to the rotated position of the rotor, as will later appear.

The rotor as thus formed is enclosed and journaled within a casing, enerally designated by the numeral 8. In the case of the motor unit M the casing comprises end plates 8| and 82 (Fig. 6), and a peripheral shell 83, the whole being joined by spaced tie bolts 81]. Interiorly of the casing the end plates carry fixed eccentric bosses 84, within which, concentrically of the casing, are journaled the shaft I0 and the hub II of the rotor.

Mounted upon and concentric with relation to the eccentrically disposed boss 84 is the eccentric disk 3. In order properly to balance the forces involved, one such disk is disposed preferably at each side of the rotor I. The interconnection between the eccentric disk 3 and the rotor I must be such that while it insures conjoint rotation of the two, likewise it will permit relative angular and translational shifting of one with respect to the other, for the reason that they rotate upon axes which are not coaxial, but which are eccentrically disposed. It has been found that an eccentric connection or interlock between the eccentric disk 3 and the rotor I, such as is shown at 5, will permit the necessary relative movement, K

while yet maintaining a proper interconnection between them at all times, without slack or lost motion. Moreover, it has but slight movement, and produces little wear. It consists of a cylindrical body received in each of the apertures I5 of the rotor, each having at its ends eccentric pins 53, which are received in apertures 35 of the eccentric disk 3, suitably spaced to receive these pins 53. Instead of the body 5 received in the aperture I5, and the eccentric pin 53, the same result will follow if a mere link is used, interconnecting the disk 3 and rotor I, provided the two pivots of such a link are spaced by the proper amount.

It should be observed at this point that the spacing of the axes of the cylinders 5 and their respective pins 53, namely, the eccentricity of this interconnecting or interlocking element, is identical with the spacing or eccentricity of the axes of the rotor I and eccentric disk 3. Moreover, not only are the spacing of these two pairs of axes the same, but the offset is at the same side of the principal axis. In other words, the off-set of the axis of the pins 53 from the axis of the cylinder 5 is in the same sense as the offset of the eccentric disk 3 from the axis of the rotor I. All these axes are parallel, of the same spacing, and in the same sense. In the pump, later described, wherein the eccentricity is adjustable, all such adjustments are made simultaneously, are identical in amount, and are in the same sense.

If we consider the eccentricity to be represented by e, the distance from the axis I9 (see Figure 15) of the rotor to the axis of interlock 5 to be r, and the distance from the disks axis 3a to the axis of pin 53 to be r and to be equal to r, then in the upper dead center position the lines 1' and r coincide, and the distance from the axis I9 to the axis of 5 is r-l-e; likewise the distance from the axis 39 to the axis of 53 is r+e. If the parts now revolve through the lines connecting these points pass through the stage of a parallelogram and become a rectangle. The radii r and r no longer coincide, but have been laterally displaced in what may be termed a positive sense. A further advance of 90 brings them back to coincidence, but now in a negative sense, and r-e equals r'e. A further 90 advance separates them again by the spacing e, and a final 90 advance returns them to their original position.

Since, in the positions 90 beyond and 90 before the initial position, the ratio r/r is always unity, and since likewise the ratio in all other cases, r+e/r+e, is unity, it follows that the interlock 5 must always rotate in its socket H5 at exactly the same rotational (angular) speed as the rotor I about its axis, but in a reverse sense. The net result is that the interlock 5 appears not to rotate at all, but to revolve orbitally about the axis of the rotor, through positions wherein a line joining the axes of 5 and 53 are always parallel to any previous position. Also, one or more such interlocks, so related, will serVe to maintain the rotor and disk in their related positions, in conjunction with the eccentric 84. Preferably as many such interlocks as there are cylinders, equiangularly spaced about the rotor, are employed, for equal distribution of the load.

It should be noted that the interlock 5 might equally well be received in the eccentric disk 3 and the pins 53 in the rotor I, or might be re placed, as already suggested, by a simple link.

Now it may be seen that the function of interlocking the rotor I and eccentric disk 3 for conjoint rotation is assigned solely to the elements 5, and that they maintain such interlock without slack. The interconnection between the pistons and the eccentric disk may now be substantially solely for the purpose of effecting reciprocation of the pistons, rather than partly for the purpose of dragging the eccentric disk around with the rotor. However, the interconnection between the pistons and the eccentric disk must also be such as will permit the relative angular and translational movement during rotation between the cocentric disk and the axis of each piston, and must be such as will not oppose the interlocks 5 by producing any tendency to assist or retard rotation of the disk 3 relative to the rotor I.

To this end there is mounted upon each end of the piston crosshead 25, by means of the pivot pins 26, a rocker arm 6. This rocker arm, though shown of triangular shape, is in effect a rigid rocker arm pivoted intermediate its ends. Preferably, for proper balance of mechanical forces, there is one such rocker arm at each side of each piston. The connection is completed by means of links BI (see Figure 11) having one crank pin 52 which is pivoted in the end of the rocker arm 6, and another crank pin 53 which is pivoted within an aperture 36 in the eccentric disk 3. Certain relationships which concern the length and location of the links 6| will be dealt with later.

The rocking of the rocker arm 6 about its pivot 26 avoids any appreciable tendency to cock the piston sidewise. The use of the pairs of links 6|, at opposite ends of the rocker arm, permits one to be tensioned while the other is in compression, for only thus are forces produced which will rock the rocker arm or, without a rocker arm, will cook the piston. The apparent translational movement of the disk 3 relative to the rotor, as both rotate from an initial upper dead center position (see Figure 15) to a position up to 90 from that initial position, advances the leading link 6| relative to the piston, causing an outward thrust upon its end of the rocker arm. The rocker arm rocks, thereby avoiding cocking, but in so doing tends to advance the trailin link 6! even more than the translational movement would require. There results a forward thrust upon the eccentric disk 3; however, since the disk 3 is interlocked with the rotor by the interlock 5, a reaction oc curs, resulting in outward component upon the piston by way of both links and the rocker arm. If there were no interlock between the disk 3 and rotor i no such reaction could occur; the rocker arm could not be pivotedupon the piston, for the links would have to thrust directly upon the piston or some element rigid therewith. The use of an interlock between the rotor and the eccentric disk is, therefore, the secret of the success of this invention, whence flow the'other advantages which were not capable of realization without provision for independently interlocking for conjoint rotation, without slack, the rotor and eccentric disk.

Reverting to the linkage interconnecting the eccentric disk and each piston, and governing the reciprocation of the latter, it should be noted that a single long link directly interconnecting the disk and each individual piston would serve equally well to effect reciprocation of the piston, and would not appreciably generate any cooking tendency. It would tend to produce a variable rate or reciprocation, at different phases of such reciprocation and of revolution, rather than a steady, even rate. motor could be kept precisely in phase, at all delivery ra-tes, any tendency in one to produce a puleating delivery would be absorbed by the companion tendency to produce in the other an opposite pulsating repeption and delivery; one

would cancel out the other. As a matter of fact, tendency to pulsation is more theoretical than actually noticeable. However, any such diffic-u-lties can be avoided by a steady rate of piston reciprocation. The linkage arrangement shown and described, including the rocker arm 6, is therefore preferred, but my invention is to be understood as including the equivalent (for most purposes) form mentioned.

With respect to fluid supply and discharge, the casing head 82, to which the conduits A and B connect, is provided with a chamber 81 which. is divided diametrically by a partition 88 (see Fi ures and 7)- to segregate the fluid delivered at A from that discharging by way of B, and to direct the fluidto and from the appropriate ports [-3. There would normally be an odd number of cylinders, and consequently an odd number of ports, so that when. one port is closed by the partition d815,, others are opened, even though one port may stop on dead center. The odd number of cylinders makes for smoother operation.

The pump unit is similar to the motor unit just described, and like parts will be designated: by the same reference numerals with primes suflixed.

If the pump and associated The pump casing 8"is similar to the motor casing 8, but is provided with guide elements 89 engageable in guide ways 91 in the fixed guide fraame 98'. Furthermore the shaft ill and the hub H are journaled, not in the casing 8", but in suitable bearings 9E internally directed from the fixed guide frame 98, and'the eccentrics 84' are slotted at 84" (see Figures 2 and 3) so that the casing 8 may move, in this instance vertically, with respect to the shaft l9" and hub H or their immediate bearings 96. By such adjustment the eccentricity of the eccentric disk 3 relative to the rotor i may be varied. In the arrangement shown it may be varied from a maximum eccentricity at one side through zero eccentricity to a like eccentricity at the opposite side, thereby reversing the direction of flow of the fluid in the conduits A and B, and the sense or rotation of the shait 10, while the sense of rotation of the shaft l0 continues unchanged.

Since the rotor i must be interlocked with the eccentric disk 3', provisions must be made in these interlocking means, in the pump unit, to permit similar and simultaneous adjustment of the eccentrici-ty oi the several interlocking means, and of the disk and rotor. Thus, instead of the interlocking means such as is shown in Figure 13, and which is used in the motor unit, there is employed in the pump unit an interlocking means such as is shown in detail in Figure 12. This unit consists of a cylindrical body 5", as before described, received in the recess id in the rotor l, and its eccentric pins 53' are received as before in the socket of the eccentric disk 3, but the pins 53 are not fixed with relation to the axis of the cylindrical element 5-, but are slidable. Thus: each pin 53 may be provided with a dovetailed head 52 received within a complemental groove 54 in the cylindrical bod 5,

' whereby, as the casing 8 and the eccentric disk 3 journaled therein are adjusted with respect to the axis of. the shaft it) and rotor l, the 53 are adjusted simultaneously and correspond ingly with respect to the axis of the corresponding cylindrical element 5-.

Here again it should be emphasized, as best seen in Figure 3, that the slots 54 are parallel to the guide Ways 9'! for each cylinder and in all p0 sitions of every cylinder, so that at all times, and in any rotated positionof the pump P, the adjustment, may be made to vary the rate of delivery 01" the pump while still retaining the rotative interlock, with no slack, between the eccentric disk and the: rotor.

For one special case, namely, when the eccentrio disk. has been rotated so thatit lies coaxially of the rotor, the eccentricity of the disk is zero, and no delivery from the pump. will. occur. In consequence, if this pump is connected to. a companion. motor unit, no drive. will result at the motor shaft It. However, in all other positions of adjustment, whether positivev or negative, some delivery from the pump. will occur, and there will be corresponding rotation of the motor, as aspe'ed dependent upon the pumps instantaneous delivery rate, and in a sense dependent upon whether the pumps adjustment is positive or negative.

Reference to Figure 15 will show in some measare the angles and the forces involved. It 39 be considered the axis of the eccentric disk 3', and (a the axis of the rotor i, then the rocker arms 6 and the links 6;! will assume the several positions shown in Figure 15' during: a cycle of one revolution, and the interlocking element 5" with its pins 53' will likewise retain the positions indicated. These latter elements, then, interlock the rotor and eccentric disk to effect rotation of the latter by and during rotation of the rotor, and maintain the two in proper operative relationship, but this causes some angular and translational movement of the eccentric disk and its radii with respect to the axis of each radially positioned piston and cylinder. The axes of the cylinders and pistons are indicated at R, and it will be observed that there is material displacement from the upper dead center position to positions at either side thereof, and then a gradual return as parts go through another dead center position at the bottom of the revolution, and a reversal as the revolution continues. This results in a rocking of each rocker arm 6 about its pin 26, and an even greater rocking of the links Bl with respect to the rocker arm 6'. The links 6 l must be of sufiicient length, with regard to this rocking movement of the rocker arm 6', that the crank arms 6| never quite reach a line from the pivot 62' to the center IQ of the rotor. However, by reason of the fact that the rocker arm 6' (and, in the motor unit, the rocker arm 6) are free to rock, the links 6| both accommodate the translational movement of the pistons and cylinders with relation to the eccentric disk, to avoid side thrust on the pistons, and in addition the forces are so applied to the eccentric disk that there is in no instance any backward thrust upon the same.

It will be noted that the oscillatory movement of the rocker arm 6, the links 6|, the interlocking element '5 and its pins 53, and the corresponding parts in the pump unit, are slight, and at slow speed. It follows that these may be simple bearings, and it is not necessary to install elaborate antifriction bearings at the several points of wear. It follows further than the construction of the unit may be greatly simplified and its cost lessened materially. Moreover the principal loads apply only to the bearings of the shaft I and the hub l I, and to the disk 3, and these may be suitably supported, but in no instance is it necessary to employ large exterior cylindrical bearings, that is, bearings such as would encircle the rotor.

I claim as my invention:

1. A hydraulic power transmission unit or the like comprising a rotor having radial cylinders, pistons therein, a disk revoluble about an axis parallel to but disposed at a predetermined eccentricity from the rotors axis, means interlocking the rotor and disk for conjoint revolution, each about its own axis, and articulated means interconnecting each piston with said disk, comprising a rocker arm pivoted between its ends upon the piston, and links connecting each end of the rocker arm with the disk.

2. A hydraulic power transmission unit or the like comprising a rotor having radial cylinders, pistons therein, a disk revoluble about an axis parallel to but disposed at a predetermined eccentricity from the rotors axis, means interlocking the rotor and disk for conjoint revolution, each about its own axis, and articulated means interconnecting each piston with said disk, comprising a rocker arm pivoted between its ends upon the piston, and links connecting each end of the rocker arm with the disk, the links being directed inwardly towards one another, and their length being so chosen, relative to the maximum eccentricity of the disk and the length of the rocker arm, that in no operative position will they reach 10 coincidence with a line, extended, connecting their pivot upon the disk and the axis of the disk.

3. In a hydraulic power transmission unit or the like, a rotor having radial cylinders, pistons therein, an eccentric disk revoluble about an axis disposed at a predetermined eccentricity to the rotors axis, two means connected for conjoint rotation, one journaled in the rotor and the other in the disk and disposed relatively at the same eccentricity as the disk and rotor, interlocking the rotor and disk for conjoint revolution each about its own axis, means connecting each piston with said disk to efiect reciprocation of the piston in its cylinder by reason of the eccentricity of the eccentric disk, and means to vary the eccentricity of the disk relative to the rotor, and, simultaneously and equally, in the same sense, the eccentricity of the interlocking means.

4. A hydraulic power transmission unit comprising a rotor having radial cylinders, pistons therein, a disk revoluble about an axis disposed at a predetermined eccentricity to the rotors axis, an eccentric device journaled in the disk and rotor, respectively, offset from the axis of each, and of like eccentricity, to interlock the disk and rotor for conjoint revolution, each about its own axis, and a plurality of links pivotally interconnected to each other, operatively interconnected between each piston and the disk, and pivotally engaged with each thereof, to govern reciprocation of the piston as the rotor and disk revolve, in accordance with their relative eccentricity.

5. A hydraulic power transmission unit con prising a rotor having radial cylinders, pistons therein, a disk revoluble about an axis disposed at a predetermined eccentricity to the rotors axis, an eccentric device journaled in the disk and rotor, respectively, ofiset from the axis or" each, and of like eccentricity, to interlock the disk and rotor for conjoint revolution, each about its own axis, articulated linkage means pivoted. to each piston and to the disk, and interconnect ing the same to govern reciprocation of the piston as the rotor and disk revolve, in accordance with their relative eccentricity, and means to vary the relative eccentricity of the rotor and disk, and, correspondingly, of the interlocking means.

6. In a hydraulic power transmission unit, a rotor having radial cylinders, a piston in each cylinder, an eccentric disk disposed at a predetermined eccentricity to said rotors axis, means interlocking the rotor and the eccentric disk for conjoint revolution, including at least one member pivoted in one thereof upon an axis paralleling the rotors axis, and having a pin pivoted in the other and disposed eccentrically of such first pivot axis along a line parallel to and by an amount equal to the eccentricity of the eccentrio disk, and means connecting each piston with the eccentric disk to effect reciprocation of the iston in its cylinder in accordance with the ec centricity of the eccentric disk, formed and arranged to permit limited angular and translational movement of the eccentric disk relative to each pistons axis, and means to vary the eccentricity of the rotor and, simultaneously, of the rotor-disk interconnecting means, between desired low and high limits.

7. In a hydraulic power transmission unit, a rotor having radial cylinders, a piston in each cylinder, an eccentric disk disposed at a predetermined eccentricity to said rotors axis, means interlocking the rotor and the eccentric disk for conjoint revolution, including at least one member pivoted in one thereof upon an axis paral1eling the rotors axis, and having a pin pivoted in the other and disposed eccentrioally of such first pivot axis along a line parallel to and by an amount equal to the eccentricity of the eccentric disk, and means connecting each piston with the eccentric disk to eiTect reciprocation of the piston in its cylinder in accordance with the eccentricity of the eccentric disk, formed and arranged to permit limited angular and translational movement of the eccentric disk relative to each pistons axis, and means to vary the eccentricity of the rotor and, simultaneously, of the rotor-disk interconnecting means, between zero and a desired upper limit at either side of Zero.

8. A hydraulic pump or motor comprising a rotor having radial cylinders, pistons therein, a disk rotatable conjointly with the rotor and having its axis displaced by a given amount from the rotors axis, a plurality of angularly spaced interlocking elements each having a body journaled in the rotor, and having, pivotally received in the disk, a pin offset from its bodys axis by an amount equal to the eccentricity of the disk relative to the rotor, and in parallel senses, whereby to retain the disk in its eccentric relation to the rotor, without slack, throughout their rotation, means yieldable transversely of each pistons axis in the common plane of all their axes, to join said piston and the eccentric disk, for reciprocation of the piston during a revolution of the rotor, guide means paralleling the plane common to the rotor and disk axes, and complemental guide means for adjustment of the disk, to vary its eccentricity, each interlocking body element having a guide parallel to said guide means, and each interlocking pin having guide means complemental thereto and guided therein, for corresponding adjustment as the eccentricity of the rotor and disk is varied, to maintain the eccentricity of the rotor and disk, and of the eccentric pin and eccentric body, respectively, always alike.

9. A hydraulic power transmission unit comprising a rotor having a plurality of radial cylinders and, intermediate the cylinders, a plurality of angularly-spaced cylindrical bores parallel to its axis; a casing wherein said rotor is journaled; an eccentric boss carried by said casing; a disk journaled upon said boss; an interlocking device to effect conjoint revolution of the rotor and disk, comprising a body journaled in each of said rotor bores and a pin carried thereby, offset from the bores axis by an amount equal to the eccentricity of said boss, and pivoted in said disk; a piston in each cylinder; a rocker arm pivoted be- 12 tween its ends upon each piston; a crank arm pivoted upon each end of each rocker arm, and pivoted at its inner end upon said disk, the spacing of the pivots of the two crank arms on each rocker being greater than the spacing of their pivots upon the disk.

10. A hydraulic power transmission unit comprising a. rotor having a plurality of radial cylinders; a piston in each cylinder; a casing wherein said rotor is journaled; a fixed guide frame, the casing and guide frame having interengaged guide means for linear adjustment of the casing relative to the frame; a circular bearing supported by the guide frame within the casing, and centrally open to receive the rotor and its journals, and to permit adjustment of the casing into and from positions of eccentricity relative to said bearing, along a line parallel to said guide means; a disk journaled in said bearing, and by such adjustment being variable in its eccentricity relative to the rotor; means interlocking the rotor and disk for conjoint revolution, each about its own axis, comprising at least one member journaled in the rotor, outwardly of the latters axis, and a member journaled in the disk, said members being positively engaged for driving, but relatively adjustable by such adjustment of the easing, along a line parallel to said guide means, whereby their respective axes are always maintained at the same spacing as the rotor and disk axes; and means interconnecting each piston and the disk to effect reciprocation of the piston in accordance with the relative eccentricity of the rotor and disk as they revolve, said interconnecting means being arranged to accommodate relative translational movement as each pistons axis moves into and from coincidence with a plane common to the axes of the rotor and disk.

- JOHN E. LUNDEGARD.

REFERENCES CITED The following referen'ces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 658,014 J iinsson Sept. 18, 1900 683,834 Beckfield Oct. 1, 1901 717,897 McCulloch Jan. '6, 1903 725,130 Peck Apr. 14, 1903 932,033 Krone Aug. 24, 1909 1,243,494 Dunning Oct. 16, 1917 2,027,356 Erling Jan. '7, 1936 2,099,630 Schneider Nov. 16, 1937 2,205,913 Stacy June 25, 1940 2,257,792 Fletcher Oct. 7, 1941 

